La nigra sako estas mia.

In Esperanto, adjectives end in -a. So nigra means black and describes the noun sako.

• nigra sako = black bag
• granda sako = big bag
• nova sako = new bag

The -a ending tells you the word is an adjective.

La is the definite article, meaning the.

So:

• la nigra sako = the black bag
• nigra sako = a black bag / black bag depending on context

Esperanto has la for the, but it does not have a separate word for a/an. If there is no article, the noun is usually indefinite or just general.

In Esperanto, nouns end in -o.

So:

• sako = bag
• domo = house
• libro = book

The -o ending marks the word as a noun.

Here mia means mine, not my.

In Esperanto, possessive words like mia can be used in two ways:

• mia sako = my bag
• La sako estas mia = The bag is mine

So in this sentence, mia stands alone and means mine.

Yes. Possessive words such as mia, via, lia, ŝia, ĝia, nia, ilia behave like adjectives in Esperanto, so they normally have the -a ending.

Examples:

• mia libro = my book
• la libro estas mia = the book is mine

Even when English changes my to mine, Esperanto keeps the same basic form: mia.

Because Esperanto verbs do not change according to person or number.

Estas always means am / is / are depending on context.

So:

• mi estas = I am
• vi estas = you are
• la sako estas = the bag is
• ili estas = they are

This is much simpler than English, where the verb changes.

This is the normal Esperanto sentence pattern:

subject + verb + complement

So:

• La nigra sako = subject
• estas = verb
• mia = complement

Literally: The black bag is mine.

Esperanto word order is fairly flexible, but this is the most neutral and common order.

The -n ending usually marks the direct object.

But in this sentence, there is no direct object. It is a linking sentence with estas (is), connecting the subject to a description or identity.

• La nigra sako estas mia. = The black bag is mine.

Here, la nigra sako is the subject, and mia is not an object; it is a predicate complement. So no -n is needed.

Yes. In Esperanto, adjectives agree with the nouns they describe in number and case.

Here:

• sako is singular
• it has no -n
• so the adjective is also singular and has no -n

That is why it is nigra sako.

Compare:

• la nigra sako = the black bag
• la nigraj sakoj = the black bags
• mi vidas la nigran sakon = I see the black bag

The adjective changes to match the noun.

You usually would not say that in normal Esperanto. The most natural place for the adjective is before the noun:

• la nigra sako

Putting the adjective after the noun is possible in some contexts, especially for style or emphasis, but it is less basic and less common for learners. The standard beginner form is:

• La nigra sako estas mia.

A simple pronunciation guide:

• La = lah
• nigra = NEE-grah
• sako = SAH-koh
• estas = ES-tahs
• mia = MEE-ah

A helpful thing about Esperanto is that pronunciation is very regular: words are usually pronounced exactly as they are written.

Yes. Mia can show that something belongs to me, is associated with me, or is mine in whatever sense the context makes clear.

For example:

• La libro estas mia. = The book is mine.
• La ideo estas mia. = The idea is mine.

So in La nigra sako estas mia, it means the black bag belongs to me.